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Discussion Starter · #1 ·
I have a carbed 860 in an xm chassis and am looking for a little more. I recently picked up a bondi air box dirt cheap to play around with next winter. I am running the skinz helium hood with their intake shelf and was thinking of running a 3.5" tube from the bondi box to the intake shelf with a filter on the end. Has anyone ran such a big intake on a doo? Just curious what it will do. The skinz tube to the intake shelf is maybe 2.5" so it should increase air flow quite a bit.
 

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I ran my old 860 with a Bondi air box in an XP chassis with XP upper air box. I felt the single air intake on the XP upper box was a disadvantage in some conditions.

Your skinz set up should be an advantage... for you. Try and keep the air temp sensor in the main tube. Just seems to work better there.
 

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Pretty much what I did on my 860r xp was I got rid of the upper airbox and made a adaptor off the horn where the air temp sensor is to go to a piece of 4" flex pipe and from there it goes to my intake that is where the headlight was.
Also I got 2 2 1/2 holes in line with the carbs on the lower box and some smaller ones in the box on the panel side all lined with some slp material and also vent holes in the side of the panel by the air box.
I've ran it for many years like this with zero issues, and never really needed to wipe off snow on my intakes.
I could get some pictures but my sled is pretty tucked away in storage right now.
 

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Discussion Starter · #4 ·
Pretty much what I did on my 860r xp was I got rid of the upper airbox and made a adaptor off the horn where the air temp sensor is to go to a piece of 4" flex pipe and from there it goes to my intake that is where the headlight was.
Also I got 2 2 1/2 holes in line with the carbs on the lower box and some smaller ones in the box on the panel side all lined with some slp material and also vent holes in the side of the panel by the air box.
I've ran it for many years like this with zero issues, and never really needed to wipe off snow on my intakes.
I could get some pictures but my sled is pretty tucked away in storage right now.
Awesome, this is exactly what I'll be doing. Building off the stock horn so that the sensor can stay mounted in the same spot. Glad to hear it works for you. Would you care to share what you run as far as clutch setups?
 

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Awesome, this is exactly what I'll be doing. Building off the stock horn so that the sensor can stay mounted in the same spot. Glad to hear it works for you. Would you care to share what you run as far as clutch setups?
I have custom ground ramps that I make myself, CR-8 helix, 2mm oversized rollers, can't remember the pin weights and what springs. I did a lot of mods and built stuff, the sled rips.
It have to look in my box of springs on what I was using. Haven't rode the sled for a few years.
 

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Discussion Starter · #6 ·
I have custom ground ramps that I make myself, CR-8 helix, 2mm oversized rollers, can't remember the pin weights and what springs. I did a lot of mods and built stuff, the sled rips.
It have to look in my box of springs on what I was using. Haven't rode the sled for a few years.
How did the airbox affect jetting? I'm just curious how much I'm going to have to play around with it.
 

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Before I even made the new intake I changed the 480 mains to 500’s and 40thou shims for the needles. Stock the sled was lean in the mid range, can’t remember what my etg’s were but they were high. Than I did the 2 holes in the back of the lower box first before making the new intake. Even doing that my etg’s stayed pretty safe. Than I tossed in a full ported 860, just to smile bigger.
 

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The fun thing with carbs is the more air intake, the more fuel is drawn.
Pretty confusing.. I am thinking of jetting up one size main when I install the intake and go from there. Is this the right approach?
Take a common 10 thou overbore size of a 500SS. The added air intake will also draw more fuel through the jets. The way to see this is by measuring the Air/Fuel ratio.

The idea of a custom airbox is to draw more air to compress for more power. Where is this added power, 5,000, 6,000, 7,000 or 8,000 rpm? 99% of all talk about power references wide open throttle, yet the hardest trail riders use wot much less than 1% of the time for spurts and impressing their buddies. This is fine and I do the same. The point is, at what rpm and load range is this added power being made with any performance mod?
 

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Discussion Starter · #12 ·
Finally got around to finishing the intake. Ended up with a 3.5" tube off the Bondi air box to a K&N filter with pre filter in the helium hood intake shelf. I previously had a stock air box with holes drilled in the back and feel like that was causing some weird swirl as I was always getting a lot of fuel/oil in my air box (premixed so it wouldn't evaporate). Running around the yard a little the new setup feels more snappy. Will be interesting to get it out on the snow.
 

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Looks good.

If your reeds are on the way out? You will get fuel/oil mix in the air box. Also if you are a little rich on the needle setting it will fuel up the box.
 
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